Introduction to Three Dimensional Geometry

Q1.If direction cosines of a line are (l, m, n), what are direction cosines of the line in the opposite direction?

• A(1/l, 1/m, 1/n)
• B(m, n, l)
• C(–l, –m, –n)
• D(l, –m, n)

Q2.Find the distance between (1, 2, 3) and (4, 5, 6).

• A3√2
• B3√3
• C3
• D9

Q3.The direction ratios (2, –3, 4) and (–4, 6, –8) represent:

• APerpendicular lines
• BThe same line (proportional)
• CParallel lines in opposite directions
• DBoth b and c

Q4.The point on the y-axis equidistant from (3, 1, 2) and (5, 5, 2) is:

• A(0, 3, 0)
• B(0, 4, 0)
• C(0, 5, 0)
• D(0, 2, 0)

Q5.Three points A(1, 1, 1), B(2, 2, 2), C(3, 3, 3) are:

• AVertices of an equilateral triangle
• BCollinear
• CVertices of a right triangle
• DNon-collinear